It is generally conventional in the above-ground swimming pool art to provide an entrance for the pool and, at separate locations, a skimmer and a return. The entrance may be associated with a deck in which case it consists of an outside ladder to the deck, and another ladder within the pool. Alternatively, it may consist of simply an A frame ladder assembly which extends over the pool wall. The skimmer is customarily mounted in such a manner that it projects through the side of the pool wall and the liner thereof. This is also true of the return.
The relatively standard A frame ladder assembly is customarily supported only at its bottom and tends to be somewhat unstable. While pools provided with a deck to the exterior of the pool have generally stable entrances, these are considerably more expensive than the less expensive A frame entrance.
By having the return and skimmer pass through the liner of the pool, the water flow, during operation of the pump, does not follow the curvature of the pool but has to change directions causing dead spots within the pool. Algae tends to grow in these dead spots and also dirt will settle in dead spots. This requires an increase in filter operation, use of chemicals and vacuuming compared to a pool without dead spots.
In addition, the cutting of the galvanized steel wall of the pool wall as well as the cutting of the vinyl at the location of the skimmer and the return also causes numerous disadvantages. Thus, it is necessary to provide for gaskets to minimize the possibility of leaking in this area. In addition, when galvanized walls are cut to receive the skimmer and return, it leaves raw steel exposed to the cut. This area will rust and cause a weakness in the wall as well as an objectionable rust stain in the area of the skimmer. By having the skimmer mounted in the pool wall it is not possible to fill the pool to its maximum depth. Thus, the water in the pool will not be higher than the center of the skimmer opening, resulting in a total depth of approximately 3 ft. 5 in. in most pools having 4 ft. high walls. Thus, while the pool is sold as a 4 ft. pool it is in fact only 41 inches deep in its normal operation.
In order to prepare the pool for winter, it is desirable to either remove skimmers or insure that no water is left within the skimmer since the freezing of water within a skimmer may cause the skimmer to break. When the skimmer is mounted on the wall it cannot readily be removed because it is difficult to relocate it exactly in the same spot, and thus it is necessary to very carefully service the skimmer to insure that it is entirely empty of water.
In addition ice customarily will build up in a pool over winter. It is quite common where the liner is cut around the skimmer that the liner will tear due to ice slippage when the ice starts to thaw.